arm: core: mpu: Add Allow write on Flash

This patch adds the allow flash write CONFIG option to the ARM MPU
configuration in privileged mode.

Signed-off-by: Vincenzo Frascino <[email protected]>
Signed-off-by: Michael Scott <[email protected]>
Signed-off-by: David Brown <[email protected]>

Author: Vincenzo Frascino

arch/arm/core/cortex_m/mpu/Kconfig

@@ -41,7 +41,7 @@ config NXP_MPU
 
 config MPU_ALLOW_FLASH_WRITE
 	bool "Add MPU access to write to flash"
-	depends on NXP_MPU
+	depends on ARM_MPU || NXP_MPU
 	default n
 	help
 	  Enable this to allow MPU RWX access to flash memory

include/arch/arm/cortex_m/mpu/arm_mpu.h

@@ -89,8 +89,14 @@ struct arm_mpu {
 #define REGION_RAM_ATTR(size) \
 		(NORMAL_OUTER_INNER_NON_CACHEABLE_NON_SHAREABLE | \
 		 NOT_EXEC | size | FULL_ACCESS)
+#if defined(CONFIG_MPU_ALLOW_FLASH_WRITE)
+#define REGION_FLASH_ATTR(size) \
+		(NORMAL_OUTER_INNER_NON_CACHEABLE_NON_SHAREABLE | size | \
+		 P_RW_U_RO)
+#else
 #define REGION_FLASH_ATTR(size) \
 		(NORMAL_OUTER_INNER_NON_CACHEABLE_NON_SHAREABLE | size | RO)
+#endif
 #define REGION_PPB_ATTR(size) (STRONGLY_ORDERED_SHAREABLE | size | FULL_ACCESS)
 #define REGION_IO_ATTR(size) (DEVICE_NON_SHAREABLE | size | FULL_ACCESS)